Mr Robertson had to be flown to Perth for treatment for injuries he suffered in the incident.

On the opening day of the trial, prosecutor Tony Loudon told the court that Williams had earlier been punched by a friend of Mr Robertson during an altercation near the nightclub toilets.

That altercation was denied by Mr Robertson and his companions, Ian Parry and Casey Smith, in their evidence.

Mr Loudon said that Williams was not physically harmed in that incident, but had suffered 'injured pride'.

The prosecutor said Williams was seeking 'vengeance, pure and simple' when he punched Mr Robertson and also says the accused told police he "wasn't going to let them feel like they got the better of me".

The trial was shown security vision of the lead-up to the altercation and slightly obscured vision of the incident itself.

Mr Loudon said that vision did not suggest either Mr Robertson or Mr Parry were about to attack Williams.

In their evidence, both men denied confronting Williams outside the club, and denied having prior knowledge of Williams or his AFL career.

But defence counsel Tom Percy said Williams had been 'set upon' by the two men and threw the punch in a 'reflexive, self-defensive' action.

Mr Percy said Williams had been the victim of a 'cowardly attack' for no reason.

He said that had Williams been seeking retribution, as the prosecution argued, his client would have punched with his natural right fist instead of his left.

Mr Percy also argued that the injuries suffered by Mr Robertson were not serious enough to constitute grievous bodily harm.

The defence lawyer said Mr Robertson, Parry and Smith had 'hazy' recollections because of the amount of alcohol they had consumed.

The court heard Mr Robertson had a blood-alcohol reading of .029 on the night.